Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many modifications of the original technique have been proposed to try to improve the results of the pancreaticoduodenectomy described by Whipple. To evaluate these modifications, we have reviewed randomized controlled trials, meta-analyses, and well-conducted retrospective series. Neither total pancreatectomy nor extended lymph node dissections have shown an improve of survival in retrospective studies. Preoperative evidence of mesenteric or portal vein involvement does not contraindicate pancreatic resection and survival rates are similar to those of patients with no venous involvement. Prospective trials and one meta-analysis have shown neither advantage nor disadvantage of pylorus-preserving pancreaticoduodenectomy or of pancreatico-gastric anastomosis. Three trials and one meta-analysis of pancreatico-gastric anastomosis have failed to demonstrate a decrease in the risk of pancreatic fistula. Two trials suggest that the risk of fistula formation is decreased by implantation of the pancreatic remnant into the jejunum or by trans-jejunal stenting of the pancreatico-jejunal anastomosis with external drainage; but these findings are not supported by a third trial. The results of the antisecretory use of somatostatin are contradictory. Leak and fistula formation were decreased when the criteria for leakage was based on laboratory findings; but in 4 out of 5 trials, somatostatin did not decrease the incidence of clinical fistula. The use of fibrin glue to occlude the pancreatic duct or seal the cut surface of the pancreas did not decrease the rate of intra-abdominal complications. In conclusion, the pancreaticoduodenal resection described by Whipple may still be considered the gold standard for resection of pancreatic cancer. The technical experience of surgeons and their institutional support staff resulted in lower perioperative morbidity and mortality and in higher survival rates.
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PMID:[Pancreaticoduodenectomy for cancer of the head of the pancreas]. 1843 75

Functional somatostatin receptors (SSTR) are lost in human pancreatic cancer. Transfection of SSTR-1 inhibited pancreatic cancer cell proliferation in vitro. We hypothesize that stable transfection of SSTR-1 may inhibit pancreatic cancer growth in vivo possibly through cell cycle arrest. In this study, we examined the expression of SSTR-1 mRNA in human pancreatic cancer tissue specimens, and investigated the effect of SSTR-1 overexpression on cell proliferation, cell cycle, and tumor growth in a subcutaneous nude mouse model. We found that SSTR-1 mRNA was downregulated in the majority of pancreatic cancer tissue specimens. Transfection of SSTR-1 caused cell cycle arrest at the G(0)/G(1) growth phase, with a corresponding decline of cells in the S (mitotic) phase. The overexpression of SSTR-1 significantly inhibited subcutaneous tumor size by 71% and 43% (n = 5, P < 0.05, Student's t-test), and inhibited tumor weight by 69% and 47% (n = 5, P < 0.05, Student's t-test), in Panc-SSTR-1 and MIA-SSTR-1 groups, respectively, indicating the potent inhibitory effect of SSTR-1 on pancreatic cancer growth. Our data demonstrate that overexpression of SSTR-1 significantly inhibits pancreatic cancer growth possibly through cell cycle arrest. This study suggests that gene therapy with SSTR-1 may be a potential adjuvant treatment for pancreatic cancer.
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PMID:Somatostatin receptor-1 induces cell cycle arrest and inhibits tumor growth in pancreatic cancer. 1882 76

Octreotide is a somatostatin analogue binding on two receptor subtypes. In previous trials Octreotide showed inhibitory effects on tumour growth and liver metastasis in experimental pancreatic cancer. Thus we evaluated whether the new somatostatin analogue SOM-230 binding on 4 receptor subtypes has superior effects on carcinogenesis in pancreatic carcinoma. About 120 Syrian hamsters were randomised into six groups (n = 20): Gr.1: Aqua/Aqua, Gr.2: BOP/Aqua, Gr.3: Aqua/Octreotide, Gr.4: BOP/Octreotide, Gr.5: Aqua/SOM-230, Gr.6: BOP/SOM-230. Tumour groups 2,4,6 subcutaneously received 10 mg/kg body weight N-nitrosobis-2-oxopropylamin (BOP) weekly for 10 weeks, healthy control Gr.1,3,5 were given aqua. In the 17th week therapy started with Octreotide and SOM-230 for 16 weeks, after 32 weeks animals were sacrificed. Pancreas and liver were histopathologically analysed. Hepatic lipidperoxidation was determined by activities of antioxidative enzymes gluthation-peroxidase (GSH-Px) and superoxiddismutase (SOD) as well as concentration of thiobarbituric-acid reactive substances (TBARS). Incidence of liver metastases was 88.2% in Gr.2 (BOP/Aqua), it was decreased in Gr.4 (BOP/Octreo: 40%) and Gr.6 (BOP/SOM-230: 50%) (P < 0.05). Mean number/animal and mean-2-dimensional size of liver metastases did not differ between tumour groups. Comparing GSH-Px-activity in intrametastatic and extrametastatic hepatic tissue revealed a significant increase extrametastatically in Gr.2 (BOP/Aqua) and Gr.6 (BOP/SOM-230). SOD-activity in liver metastases was decreased in Gr.2 (1,801) (P < 0.05) versus Gr.4 (8,304) and Gr.6 (7,038). Intrametastatic TBARS concentration was increased in Gr.2 compared to Gr.4 (BOP/Octreotid) and Gr.6 (BOP/SOM-230) (P < 0.05). Octreotide and SOM-230 equally reduced liver metastasis in ductal pancreatic adenocarcinoma probably by a reduction of lipidperoxidation.
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PMID:Impact of Octreotide and SOM-230 on liver metastasis and hepatic lipidperoxidation in ductal pancreatic adenocarcinoma in Syrian Hamster. 1952 86

The somatostatin receptor subtype 2 (sst2) behaves as a tumor suppressor when expressed and stimulated by its ligand somatostatin in pancreatic cancer. We reveal a mechanism underlying oncosuppressive action of sst2, whereby this inhibitory receptor upregulates the expression of the secreted angioinhibitory factor thrombospondin-1 (TSP-1), as demonstrated in exocrine BxPC-3 and endocrine BON pancreatic cancer cells. The sst2-dependent upregulation of TSP-1 occurs through the inhibition of the PI3K pathway. It depends on transcriptional and translational events, involving a previously undescribed IRES in the 5'-UTR of TSP-1 mRNA. Chick chorioallantoic membrane was used as an in vivo model to demonstrate that TSP-1 is a critical effector of the inhibitory role of sst2 on the neoangiogenesis and oncogenesis induced by pancreatic cancer cells. TSP-1 reduced in vitro tubulogenesis of endothelial cells when grown in conditioned medium from pancreatic cancer cells expressing sst2, as compared to those expressing the control vector. TSP-1 inhibited tumor cell-induced neoangiogenesis by directly sequestering the proangiogenic factor VEGF, and inactivating the angiogenesis initiated by VEGFR2 phosphorylation in endothelial cells. Using human pancreatic tissue-microarrays, the expression of both sst2 and TSP-1 was shown to be correlated during the pancreatic neoplastic program. Both proteins are nearly undetectable in normal exocrine pancreas and in most invasive cancer lesions, but their expression is strikingly upregulated in most preinvasive cancer-adjacent lesions. The upregulation of both sst2 and TSP-1 tumor suppressors may function as an early negative feedback to restrain pancreatic carcinogenesis.
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PMID:Thrombospondin-1 is a critical effector of oncosuppressive activity of sst2 somatostatin receptor on pancreatic cancer. 1980

The aim of the study was to evaluate real time in vivo molecular imaging of somatostatin receptors (sstrs) using a handheld miniaturized confocal laser scan microscope (CLM) in conjunction with fluorescein-labeled octreotate (OcF) in healthy mice and murine models of neuroendocrine tumors. For CLM a small rigid probe (diameter 7 mm) with an integrated single line laser (488 nm) was used (optical slice thickness 7 mum; lateral resolution 0.7 mum). OcF was synthesized via Fmoc solid-phase peptide synthesis and purified by HPLC showing high-affinity binding to the sstr2 (IC(50) 6.2 nmol). For in vitro evaluation, rat and human pancreatic cancer cells were used and characterized with respect to its sstr subtype expression and functional properties. For in vivo confocal imaging, healthy mouse pancreatic islet and renal tubular cells as well as immunoincompetent nude mice harboring sstr-expressing tumors were evaluated. Incubation of sstr-positive cells with OcF showed a specific time- and dose-dependent staining of sstr-positive cells. CLM showed rapid internalization and homogenous cytoplasmatic distribution. After systemic application to mice (n = 8), specific time-dependent internalization and cytoplasmatic distribution into pancreatic islet cells and tubular cells of the renal cortex was recorded. After injection in tumor-harboring nude mice (n = 8), sstr-positive cells selectively displayed a cell surface and cytoplasmatic staining. CLM-targeted biopsies detected sstr-positive tumor cells with a sensitivity of 87.5% and a specificity of 100% as correlated with ex vivo immunohistochemistry. CLM with OcF permits real-time molecular, functional, and morphological imaging of sstr-expressing cell structures, allowing the specific visualization of pancreatic islet cells and neuroendocrine tumors in vivo.
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PMID:In vivo molecular imaging of somatostatin receptors in pancreatic islet cells and neuroendocrine tumors by miniaturized confocal laser-scanning fluorescence microscopy. 2023 96

Stem cells are critical in maintaining adult homeostasis and have been proposed to be the origin of many solid tumors, including pancreatic cancer. Here we demonstrate the expression patterns of the putative intestinal stem cell marker DCAMKL-1 in the pancreas of uninjured C57BL/6 mice compared with other pancreatic stem/progenitor cell markers. We then determined the viability of isolated pancreatic stem/progenitor cells in isotransplantation assays following DCAMKL-1 antibody-based cell sorting. Sorted cells were grown in suspension culture and injected into the flanks of athymic nude mice. Here we report that DCAMKL-1 is expressed in the main pancreatic duct epithelia and islets, but not within acinar cells. Coexpression was observed with somatostatin, NGN3, and nestin, but not glucagon or insulin. Isolated DCAMKL-1+ cells formed spheroids in suspension culture and induced nodule formation in isotransplantation assays. Analysis of nodules demonstrated markers of early pancreatic development (PDX-1), glandular epithelium (cytokeratin-14 and Ep-CAM), and isletlike structures (somatostatin and secretin). These data taken together suggest that DCAMKL-1 is a novel putative stem/progenitor marker, can be used to isolate normal pancreatic stem/progenitors, and potentially regenerates pancreatic tissues. This may represent a novel tool for regenerative medicine and a target for anti-stem cell-based therapeutics in pancreatic cancer.
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PMID:Identification of a novel putative pancreatic stem/progenitor cell marker DCAMKL-1 in normal mouse pancreas. 2053 4

In three experiments, hamsters with N-nitroso-bis(2-oxopropyl)amine-induced pancreatic cancers were treated for two months with bombesin/GRP antagonists RC-3095 [D-Tpi(6),Leu(13)psi(CH2NH)Leu(14)-bombesin(6-14)], RC-3910-II [D-Tpi(6),Leu(13)psi(CH2N)Tac(14)-bombesin(6-14)], RC-3940-II [Hca(6),Leu(13)psi(CH2N)Tac(14)-bombesin(6-14)], RC-3950-II [D-Phe(6),Leu(13)psi(CH2N)Tac(14)-bombesin(6-14)], somatostatin analog RC-160 (D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2), or the combination of RC-3095 with RC160. All peptides inhibited pancreatic cancers to various degrees, reducing the number of tumorous animals, lowering the weight of tumorous pancreata by 40-55% and decreasing AgNOR numbers which are indicators of cell proliferation rate. Combination therapy with RC-3095 and RC-160 did not inhibit tumors better than single peptides. Among new bombesin/GRP antagonists, RC-3940-II had the strongest inhibitory effect. RC-3950-II and RC-3095 caused similar inhibition, but RC-3910-II was less effective. Tumor inhibitory activity of the bombesin/GRP antagonists was correlated with their binding affinities to bombesin receptors on tumor cells. RC-3940-II caused 50% inhibition of specific binding of [I-125-Tyr(4)]bombesin to tumor cell membranes at 0.96 nM concentration, while the IC50 for RC-3950-II was 5.27 nM and 12.94 nM for RC-3095. Our findings suggest that in addition to RC-3095, other bombesin/GRP antagonists such as RC-3950-II and especially RC-3940-II could be further developed for therapy of human pancreatic cancer.
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PMID:Effects of new bombesin antagonists given singly or in combination with a somatostatin analog on nitrosamine-induced pancreatic cancers in hamsters. 2154 26

Estrogen and somatostatin receptors have been found in pancreatic carcinoma cells, The growth of pancreatic carcinomas has been shown to be inhibited by various endocrine treatments. In view of these findings, a well known anti-estrogen tamoxifen has been used, both as a single agent and in combination with other agents, in clinical trials in patients with unresectable carcinoma of the exocrine pancreas. The impact on survival of tamoxifen in patients with advanced pancreatic adenocarcinoma has been assessed among patients from the previously reported trials of tamoxifen as a single agent, and compared with the survival of patients treated with the synergistic combination of intravenous Onconase plus oral tamoxifen. While a few patients treated with tamoxifen as a single agent may survive for prolonged period of time, the significance of such results remains uncertain in view of the lack of significant survival difference between patients treated with tamoxifen vs. untreated controls in prospectively randomized trials, and vis a vis clearly multifactorial determination of survival. On the other hand, the synergistic combinations of agents that demonstrate favorable toxicity profiles may offer significant survival advantage, at least in some patients with advanced pancreatic cancer.
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PMID:Tamoxifen in patients with advanced pancreatic adenocarcinoma. 2159 8

Pancreatic cancer still is a significant, unresolved therapeutic challenge with nearly similar incidence and mortality rates. It is the most lethal type of digestive cancer with a 5-year survival rate of 5%. Adjuvant chemotherapy remains to be gemcitabine alone or combined with infusional 5-fluorouracil with radiation therapy. Nevertheless, only a few patients survive for at least 5 years after R0 resection and adjuvant therapy. Most patients need palliative treatment. Once pancreatic cancer becomes metastatic, it is uniformly fatal with an overall survival of typically 6 months from diagnosis. Chemotherapy is an important component of palliative care but must be administered as a part of a multidisciplinary approach, including palliation of pain, managing weight loss, and deterioration in functional status. Gemcitabine has been the standard in both locally advanced and metastatic disease. The addition of the tyrosine kinase inhibitor erlotinib prolongs median survival for only 2 weeks. While gemcitabine-based regimens are currently accepted as the standard first-line treatment of patients with locally advanced or metastatic pancreatic adenocarcinoma, there is no consensus regarding treatment in the second-line setting. It will not be untrue to say that there are no real medical breakthroughs with regards to improving the prognosis of pancreatic cancer as of 2011. On the other hand, we have made some progress in patients with advanced pancreatic neuroendocrine tumors. These patients have a 5-year survival that can range from 97% in benign insulinomas to as low as 30% in non-functional metastatic pancreatic neuroendocrine tumors. Treatment options may include surgery, transarterial chemoembolization of liver metastases, and cytotoxic therapy such as streptozotocin, 5-fluorouracil or doxorubicin. Somatostatin analogues, like octreotide, have been proven to prolong progression-free survival in patients with metastatic neuroendocrine tumors of midgut origin. In 2011, two targeted agents, a tyrosine kinase inhibitor sunitinib and mTOR inhibitor everolimus have been approved by FDA for pancreatic neuroendocrine tumors. With these approvals, U.S. physicians can now offer their patients with progressive pancreatic neuroendocrine tumors. Patients with any stage of pancreatic cancer should be considered candidates for clinical trials.
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PMID:Pancreatic neoplasm in 2011: an update. 2173 86

Many tumors highly express specific populations of G-protein-coupled receptors (GPCRs) that could be utilized for receptor-targeted therapy. We confirmed significant quantities of mRNAs specific for certain somatostatin (SST), vasoactive intestinal peptide (VIP), and bombesin (BN) receptors in various commercially available tumor cell lines. Very few of the tumor cell lines examined displayed the high receptor-binding affinity despite exhibiting the expression of appropriate mRNAs and proteins of the cognate receptors. However, binding assays establish that some tumor cell lines, such as pancreatic cancer CFPAC-1, prostate cancer DU-145, and pancreatic carcinoid BON, demonstrate high BN receptor binding. BON cells also demonstrate high somatostatin receptor (SSTR) affinity binding. We also found that tumor cell lines, such as BON and host cells expressing SST receptor subtypes 1 or 2 (CHO-R1 or CHO-R2), underwent a decrease in cell surface receptor density in multiple passages. BON and CHO-R2 cells also rapidly internalize a significant proportion of cell surface ligand-receptor complexes. The tumor cells CFPAC-1, DU-145, and BON with high receptor binding could be useful for peptide drug studies. BON cells were further applied to test SST/BN analogs and cytotoxic conjugates. Furthermore, the in vivo antitumor assay showed that the cytotoxic conjugate CPT-SST targeting all SSTR subtypes displayed a potent tumor-suppressive ability to BON tumors expressing multiple SSTR subtypes.
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PMID:Investigation of cancer cell lines for peptide receptor-targeted drug development. 2183 Sep 41


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